1. Field of the Invention
The present invention relates to a mechanical pencil whose lead can be moved down by side pushing. The present invention also relates to a mechanical pencil whose lead can be not only moved down by side pushing but also automatically moved down by the writing stoppage action of a slider away from the surface of paper or the like and in which the slider can be locked in a housed position inside the pencil when the pencil is not in use.
2. Description of the Prior Art
An automatic mechanical pencil, which can be pushed at the top thereof to move out a lead and includes a conventional one-way chuck, which holds the lead at the time of the action of writing pressure to the chuck and ceases the holding of the lead due to the resilient force of a slider and the action of a friction-causing portion fitted in the slider, at the time of the removal of the writing pressure from the chuck, to automatically move out the lead, has been recently proposed. However, since the mechanism of the automatic mechanical pencil is such that the slider cannot be completely put in by pushing the top of the pencil, the pencil has a problem that only the lower end of the slider projects out from the tip member of the pencil. Although the lead can be protruded from the lower end of the slider by pushing the lower end as the pencil remains held in a writing position, the pencil has another problem that the surface of paper or the like is contaminated by the lower end of the lead if the lower end of the slider is pushed on the paper or the like as the pencil remains held in the writing position.
A conventional mechanical pencil capable of moving out a lead by pushing the side of the pencil has problems that the constitution of the pencil is very complicated, and the holding of the outer cylinder of the pencil needs to be temporarily ceased to push the pencil at the side thereof, namely, the pencil cannot be manipulated to move out the lead as the pencil remains held in a writing position.